Magnetic tape cartridge

ABSTRACT

The present invention aim at providing a magnetic tape cartridge, which can be assembled using an automated products line by enabling the assembling operation of a spring member and a slide door with ease.  
     For attaining these problems, there is provided a magnetic tape cartridge comprising a magnetic tape cartridge comprising; an opening provided on one side wall of a cartridge case, and is used for tape drawing; a slide door slidably supported by a guide part disposed along said one side wall, and said slide door is used for achieving the shutting-and-opening operation of said opening; a spring member for impelling said slide door to the shutting direction side, and is placed on said guide part; and a leading part for leading one end part of said spring member to a spring engaging part provided on said slide door, and is provided at one end part of said spring member.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a magnetic tape cartridge, inwhich a single reel, a magnetic tape is wound thereon, is rotatablystored, and is composed of an upper half, a lower half, an opening fordrawing the magnetic tape, and a slide door for achieving theopening-and-shutting of the opening. More specifically, the presentinvention relates to a spring member, which impels a slide door to theshutting direction for shutting the opening of the magnetic tapecartridge.

[0003] 2. Description of the Related Art

[0004] In the magnetic tape cartridge used as the external recordingmedium for recording the back up data of a computer etc, a single reel,a magnetic tape is to be wound, is rotatably stored within a cartridgecase. This cartridge case is composed of an upper half and a lower half,and has a nearly flat square shape.

[0005] In the occasion of using, a magnetic tape is drawn out from thecartridge case, and is wound by the reel mounted on a read-writeapparatus. Thus the magnetic tape is traveled.

[0006] An opening for drawing the magnetic tape is formed on thesidewall of the cartridge case. This opening is normally covered forpreventing the intrusion of the dust, and is opened at the time ofdrawing a magnetic tape for recording or replaying the data on themagnetic tape using the recording-writing apparatus.

[0007] In the magnetic tape cartridge as represented by LTO (Linear tapeopen circuit) standard among these conventional magnetic tapecartridges, a slide door for achieving the opening-and-shutting of theopening is arranged so as to slide along the inside of the sidewall ofthe cartridge case.

[0008] The slide door is fit with a guide groove formed on the upperhalf and the lower half, respectively, for smoothly achieving theopening-and-shutting movement along the guide grooves. The slide door isimpelled to the shutting direction by the spring member except for atthe time of using.

[0009] As an construction of such type of magnetic tape cartridge, asshown in FIG. 17, an guide groove 101 b is provided on the lower half101 along the side wall 101 a. A hooking part 101 d having a canaliformshape is formed on a rib 101 c provided at the inward side of the sidewall 101 a.

[0010] In this construction, a spring arm 102 a of the spring member 102is hooked on the hooking part 101 d, and a spring arm 102 b is fit on anotching part 103 a provided in the opening direction side of the slidedoor 103. Thus, the slide door 103 is impelled toward the shuttingdirection side.

[0011] For achieving the certain hooking with the hooking part 101 d, atip part 102 c of the spring arm 102 a is bent in the perpendiculardirection with respect to the rib 101 c.

[0012] On the other hand, for achieving the certain contact with thenotching part 103 a, the spring arm 102 b is bent toward the slide door103 side, and also for achieving the certain hooking and impelling ofthe notching part 103 a, a tip part 102 d of the spring arm 102 b isbent in the shutting direction side.

[0013] When assembling the magnetic tape cartridge having a conventionalconstruction, after attaching the spring arm 102 a to the hooking part101 d, the slide door 103 is attached to the lower half 101.

[0014] At this time, as shown in FIG. 18A, the slide door 103 is pushedtoward the opening direction side while keeping the condition that theopening direction side thereof is tilting downwardly, and then engagedto the guide groove 101 b.

[0015] In this assembling manner, as shown in FIG. 18B, since the bottomend of the slide door 103 is got stuck with the tip part 102 d of thespring arm 102 b, the opening direction side of the slide door 103should be picked up for releasing from the stuck condition and forachieving the assembling.

[0016] In the assembling of the spring member and the slide door,consequently, thousands of man-hours are required, and theautomatization of the product line of a magnetic tape cartridge had beenmade into the difficult.

[0017] In the assembling of the magnetic tape cartridge having astructure of shown in FIG. 19, the magnetic tape cartridge is assembledas below.

[0018] First, each parts, such as a reel, a breakable tab for preventingthe accidentally erase, and the likes, are disposed at the predeterminedposition of the lower half. And then, as shown in FIG. 19, a springmember 201 and a slide door 202 are placed on the guide groove 203 a ofthe lower half 203. Hereat, the spring member 201 is arranged in thebridging condition so that the slide door 202 is constantly impelled tothe shutting direction side.

[0019] Until the upper half (not shown) and the lower half 203 areassembled together, however, only the lower part of the slide door 202is supported by an slider stop 204 of the lower half 203. To be moreprecise, about ⅕ of an overall height length of the slide door 202 issupported. In this state, since the upper part of the slide door 202 isnot restricted, the slide door 202 tends to be lifted upwardly. Thislifting movement is caused by the urging force brought by the springmember 201 which makes the slide door 202 rotate centering on the bottomend in the shutting direction side of the slide door 202.

[0020] When the assembling of the upper half and the lower half 203 iscontinued as it is, therefore, the engagement of the slide door 202 withthe guide groove of the upper half or the lower half 203 is disturbed.As a result of this disturbance, the automatization of the product lineof the magnetic tape cartridge becomes difficult.

SUMMARY OF THE INVENTION

[0021] The present invention aim at providing the magnetic tapecartridge, which can easily assembled using the automated product lineby making the assembling operation of the spring member and the slidedoor easier.

[0022] For attaining the above described objects, there is provided amagnetic tape cartridge comprising; an opening provided on one side wallof a cartridge case, and is used for tape drawing; a slide door slidablysupported by a guide part disposed along said one side wall, and saidslide door is used for achieving the shutting-and-opening operation ofsaid opening; a spring member for impelling said slide door to theshutting direction side, and is placed on said guide part; and a leadingpart for leading one end part of said spring member to a spring engagingpart provided on said slide door, and is provided at one end part ofsaid spring member.

[0023] According to the present invention, since the guide part 72 isprovided at one end part (end part in the shutting direction side) ofthe spring member, the tip part of the spring arm is guided to thenotching part of the slide door without interference, when the slidedoor is attached to the guide part of the cartridge case onto which thespring member is disposed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is an exploded perspective view of the magnetic tapecartridge according to the present invention.

[0025]FIG. 2 is an enlarged view of the relevant part showing the slidedoor and the spring member, which are mounted on the lower half shown inFIG. 1.

[0026]FIG. 3A is a cross sectional view showing the condition that thespring member is attached to the lower half according to the presentinvention.

[0027]FIG. 3B is a cross sectional view showing the condition that theguide part of the spring member is lifted up by the slope of the slidedoor.

[0028]FIG. 3C is a cross sectional view showing the condition that theguide part of the slide door is certainly attached to the guide groove.

[0029]FIG. 4 is a front view showing the another preferred embodiment ofthe spring member.

[0030]FIG. 5 is an enlarged view of the relevant part showing the lowerhalf, the slide door, and the spring member.

[0031]FIG. 6 is a sectional view showing the condition that the springmember and the slide door of FIG. 5 are certainly attached to the guidegroove of the lower half FIG. 7 is a sectional view showing the anotherpreferred embodiment of the magnetic tape cartridge accirding to thepresent invention.

[0032]FIG. 8 is an enlarged view showing the relevant part of the upperhalf, lower half, the slide door, and the spring member according to thepresent invention.

[0033]FIG. 9 is an enlarged view showing the relevant part of the insideof the upper half.

[0034]FIG. 10A is a sectional view showing the condition that the slidedoor and the spring member is attached to the lower half.

[0035]FIG. 10B is a sectional view showing the condition that theflection of the spring member is fit with the slope of the projectionpart.

[0036]FIG. 10C is a sectional view showing the condition that the upperhalf and the lower half are assembled together.

[0037]FIG. 11 is a sectional view showing the another preferredembodiment of the magnetic tape cartridge according to the presentinvention.

[0038]FIG. 12 is a sectional view showing the other preferred embodimentof the magnetic tape cartridge according to the present invention.

[0039]FIG. 13 is a sectional view showing the another preferredembodiment of the magnetic tape cartridge according to the presentinvention.

[0040]FIG. 14 is a sectional view showing the other preferred embodimentof the magnetic tape cartridge according to the present invention.

[0041]FIG. 15 is a sectional view showing the another preferredembodiment of the magnetic tape cartridge according to the presentinvention.

[0042]FIG. 16 is a sectional view showing the other preferred embodimentof the magnetic tape cartridge according to the present invention.

[0043]FIG. 17 is an enlarged view showing the relevant construction ofthe conventional magnetic tape cartridge according to the presentinvention.

[0044]FIG. 18A is a sectional view showing the condition that the springmember is attached to the lower half of shown in FIG. 17.

[0045]FIG. 18B is a sectional view showing the condintion that thespring member is caught on the slide door.

[0046]FIG. 19 is an enlarged view showing the relevant construction ofthe conventional magnetic tape cartridge.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT

[0047] [The First Preferred Embodiment]

[0048] The explanation about the magnetic tape cartridge according tothe present invention will be carried out referring to the attacheddrawings.

[0049] As shown in FIG. 1, a magnetic tape cartridge, a cartridge case1, is composed of a lower half (one half) 2 and an upper half (anotherhalf) 3, between which a coil spring 4, a reel 5, a breakable tab 6 forpreventing the accidentally erase, a slide door 7, a spring member 8,and a IC chip 9 are stored. In the cartridge case 1, an opening 11 fordrawing a magnetic tape T out is formed ranging over the side wall 21 oflower half 2 and the side wall 31 of upper half 3

[0050] The lower half 2 is the lower half part of the cartridge case 1and is the case made of resin, such as polycarbonate and the like. Thelower half 2 is composed of a bottom wall 22 of thin thickness and fourside walls 21, 23, 24, and 25 surrounding the bottom wall 22. Ribs 26for reinforcing the rigidity of the lower half 2 as a whole is disposedat the suitable position on the lower half 2 so as not to disturb therotation of the reel.

[0051] As shown in FIG. 2, a guide groove (a guide part) 22 a is formedat the bottom wall 22 of the lower half 2 along the side wall 21. Ahooking part 26 a for hooking the spring member 8 is formed on the rib26 located near the guide groove 22 a. This hooking part 26 a has a slitshape in side viewing, and at the upper side of which is opened upward.

[0052] The slide door 7 is a plate having a nearly same thickness as thewidth of the guide groove 22 a, and the shutting direction side thereofis served as the principal-plane part 71 for covering the opening 11formed on the side wall 21. The notching part (spring engagement part)72 is formed in the opening direction side of the slide door 7.

[0053] The opening direction side of the notching part 72 is served asprotruding part 73, at the upper side of which is caved so as not tointerfere with the spring member 8, and at the bottom side of which isserved as a wedge part 74. The tip part of the wedge part 74 is formedin a wedge shape.

[0054] A shutter pull 71 b for operating the slide door 7 is provided atthe center section of side-face 71 a located at the shutting directionend of the principal-plane part 71. Among the faces formed at thenotching part 72, the face orthogonal to the opening-and-shuttingdirection is served as a depressing face 72 a, which is pushed by thespring member 8. An upper face 74 a for placing the spring member 8 isformed at the bottom end side of the depressing face 72 a in thecondition of having facing toward the direction perpendicular to thedepressing face 72 a.

[0055] A slope 74 b, descending toward the opening direction side, isformed at the opening direction end of the upper face 74 a. A tip face74 c prolonging downward is provided at the opening direction end of theslope 74 b.

[0056] The spring member 8 is composed of coil part 81 and 81 adjoiningalong the shutting-and-opening direction, a connecting part 82 forconnecting the coil part 81 and 81 each other, and spring arm 83 and 84.The spring arm 83 is prolonged from the opening direction end of thecoil part 81 and is used for fixing, and the spring arm 84 is prolongedfrom the shutting direction end of the coil part 81 and is used forpushing.

[0057] A latch 83 a for hooking on the hooking part 26 a of rib 26 isformed at the tip (end) part side of the spring arm 83 by bending thetip part so as to be orthogonal to the rib 26.

[0058] The spring arm 84 is bent toward the orthogonal direction withrespect to the principal-plane part 71, and the tip part side of whichis further bent toward the shutting direction side. A tip part 84 a (oneend part or a front end) for pushing the depressing face 72 a of theslide door 7 is thus provided. A guide part 84 b having an arc shape inside viewing is provided at the tip end side of this tip part 84 a forachieving the assembling of the cartridge case 1 with ease.

[0059] The explanation about the attaching manner of the slide door 7and the spring member 8 to the lower half 2 will be carried out.

[0060] First, as shown in FIG. 3A, hooking the latch 83 a of the springarm 83 to the hooking part 26 a of the rib 26 from the upper direction,and placing the tip part 84 a of the spring arm 84 on the guide groove22 a.

[0061] Then, inserting the slide door 7 toward the opening directionside from the shutting direction side while keeping the condition thatthe wedge part 74 and the protruding part 73 side of the slide door 7 istilting downwardly.

[0062] At that time, when the tip face 74 c of the wedge part 74 isinserted to the guide groove 22 a while pushing down the principal-planepart 71 downwardly, the slide door 7 is slid toward the openingdirection side.

[0063] When the tip face 74 c of the wedge part 74 is contacted with theguide part 84 b of the spring arm 84, as shown in FIG. 3B, since theguide part 84 b has a ark shape, the upper end of the tip face 74 ccrawls under the guide part 84 b.

[0064] Thus, the guide part 84 b is lifted by the tip face 74 c, and thespring member 8 is rotated centering on the latch 83 a of the spring arm83.

[0065] When the slide door 7 is further moved, the guide part 84 b ridon the tip face 74 c is further lifted along the slope 74 b of the wedgepart 74.

[0066] When the bottom of the guide part 84 b reaches at the top end ofthe slope 74 b, as shown in FIG. 3C, the tip part 84 a is rid on theupper face 74 a of the wedge part 74.

[0067] When the slide door 7 is further moved to the opening directionside, the tip part 84 a rid on the upper face 74 a is slid and isapproached to the depressing face 72 a.

[0068] When the bottom of the slide door 7 is completely engaged withthe guide groove 22 a, the guide part 84 b of spring member 8 is fittedwith the depressing face 72 a of the slide door 7 in the condition thatthe depressing face 72 a is pressed toward the shutting direction.

[0069] According to the present invention, the effectiveness as belowcan be obtained. Since the guide part 72 is provided, the tip part 84 aof the spring arm 84 is guided to the notching part 72 of the slide door7 without interference, thus the tip part of the spring member is notgot stuck with the slide door like a conventional construction.

[0070] In the attaching operation of the spring member and the slidedoor, the picking up operation of the spring member by the man work canbe omitted, the automation of the manufacturing line of the magnetictape cartridge can be easily achieved.

[0071] The present invention is not restricted to the above describedembodiment, and is represented by the various manner.

[0072] In the preset embodiment, the shape of the guide part of thespring member is formed in the ark shape, but another shape of the guidepart may be acceptable. For example, the shape as shown in FIG. 4 can beacceptable. To be more precise, as shown in FIG. 4, the shape, in whichthe tip part 84 a is bent upwardly in the shutting direction side andfurther bent in the right above direction at the tip end side thereof,can be acceptable.

[0073] In the present embodiment, the spring member, in which two ofadjoining coils having a prolonged spring arm, respectively, arearranged, is adopted. The spring member is not restricted to this case,any type of shapes and materials can be acceptable as long as the guidepart is arranged at the one end part of the spring member.

[0074] In the present embodiment, furthermore, the guide part is formedby bending the tip side of the spring arm. The formation manner of theguide part is not restricted to this case, any type of the guide partmay be acceptable as long as the one end part of the spring member canbe guided to the spring engaging part of the slide door without anyinterference.

[0075] For example, the cap having a lock-and-key shape with respect tothe guide part, and is made of resin etc, and is arranged at the tippart of the spring arm, can be acceptable.

[0076] The advantages brought from the present invention is not affectedeven if the shape at the tip of the wedge part 74 is not formed in thecertain plane shape. For example, when roundish shape, the cusped shape,and the like are adopted as the shape of the tip at the wedge part 74,the assembling of the magnetic tape cartridge can be achieved with ease.

[0077] [Second Preferred Embodiment]

[0078] The explanation about the second preferred embodiment of themagnetic tape cartridge according to the present invention will becarried out as below. In the following explanation, the components sameas explained in the first preferred embodiment is indicated by the samesymbols and the explanation thereof is omitted.

[0079] As shown in FIG. 5, a hooking part 26 b is formed on the rib 26of the lower half 2, so as to be prolonged to the almost mid position inthe height direction of the rib 26.

[0080] A slide door 7′ is a plate having the same thickness as the widthof the guide groove 22 a. The size of the slide door 7′ at the shuttingdirection side is established so as to cover the opening 11 formed onthe side wall 21. At the opening direction side of the slide door 7′ iscaved so as not to interfere with the spring member 8.

[0081] A hooking hole 7 a′ for connecting with the spring member 8 isbored at the vicinity of the bottom in the opening direction side of theslide door 7′. The position of the hooking hole 7 a′ is established atthe lower side than the top end of a slider stop 27 arranged at the sidewall 25.

[0082] The spring member 8 is composed of coil part 81 and 81 adjoiningalong the shutting-and-opening direction, a connecting part 82 forconnecting the coil part 81 and 81 each other, and a spring arm 83 and84. The spring arm 83 is prolonged from the opening direction end of thecoil part 81 and is used for hooking, and the spring arm 84 is prolongedfrom the shutting direction end of the coil part 81 and is used forpushing the slide door 7′.

[0083] A latch 85 a for hooking on the hooking part 26 b of rib 26 isformed at the tip (end) part of the spring arm 85 by bending the tippart so as to be orthogonal to the rib 26.

[0084] A tip part 86 a for engaging with the hooking hole 7 a′ of theslide door 7′ is formed at the tip of the spring arm 86. The tip part 86a is formed by bending the tip towards the orthogonal direction withrespect to the slide door 7′.

[0085] The length of the spring arm 86 is established longer than thespring arm 85, so that two of adjoining coils 81 and 81 may be in thehorizontal condition, when a latch 85 a of the spring arm 85 and the tippart 86 a are engaged with the hooking part 26 b and the hooking hole 7a′, respectively.

[0086] The explanation about the attaching manner of the slide door 7′and the spring member 8 to the lower half 2 will be carried out withreferring to FIG. 5 through FIG. 6.

[0087] First, engaging the tip part 86 a of the spring arm 86 with thehooking hole 7 a′ of the slide door 7′. Next, hooking the latch 85 a ofthe spring arm 85 to the hooking part 26 b of the rib 21 from the upperdirection. Then, putting down the slide door 7′ on the guide groove 22 aby moving the slide door 7′ to the opening direction while weightingdown the spring member 8.

[0088] Finally, sliding the slide door 7′ to the shutting directionside, and bringing the bottom end in the shutting direction side of theslide door 7′ into contact with the slider stop 27 of the side wall 25.Thus, as shown in FIG. 6, the slide door 7′ is engaged with the guidegroove 22 a formed on the lower half 2.

[0089] Since the latch 85 a of the spring member 8 is supported by thehooking part 26 b and the tip part 86 a of the spring member 8 isengaged with the hooking hole 7 a′, the slide door 7′ is impelled to theshutting direction side by the spring member 8 compressed between theslide door 7′ and the hooking part 26 b.

[0090] At that time, the position the hooking hole 7 a′ is bored islower than the top end of the slider stop 27, and the position latch 85a of the spring member 8 is supported by the hooking part 26 b is higherthan the hooking hole 7 a′. Thus, the slide door 7′ and the springmember 8 are attached to the lower half 2 in the condition that theurging force towards the lower side and the shutting direction side isapplying to the hooking hole 7 a′ of the slide door 7′.

[0091] According to the present preferred embodiment, the effectivenessas below can be obtained.

[0092] Since the urging force towards the lower side and the shuttingdirection side with respect to the slide door 7′ is applied to the slidedoor 7′, the lifting movement of the slide door 7′ caused by therotation centering on the bottom end in the shutting direction end ofthe slide door 7′ is prevented.

[0093] Therefore, the attaching operation of the spring member 8 and theslide door 7′, and the assembling operation of the lower half 2 and theupper half 3 can be achieved with ease. Thus, the automation of themanufacturing line of the magnetic tape cartridge can be easilyachieved.

[0094] The present invention is not restricted to the above describedembodiment, and is represented by the various manner.

[0095] In the present embodiment, the hooking part 26 b is provided soas to be located at the higher position than the guide groove. Thepresent invention is not restricted to this case, any type ofconstruction can be adopted as long as the tip part in the openingdirection side of the spring member is located at the higher positionthan the position of the tip part in the shutting direction side.

[0096] When a helical torsion coil spring B1 having a zigzagged shapeand the coil part B11 is arranged at the flection part thereof isadopted, as shown in FIG. 7, the construction, in which a hooking hole26 c for hooking the end part in the opening direction side of thehelical torsion coil member B1 is provided, can be acceptable.

[0097] In this construction, the end part in the opening direction sideof the helical torsion coil member B1 is supported by the hooking hole26 c, the end part in the shutting direction side thereof is placed onthe guide groove 22 a and presses the bottom part of the slide door D1to the shutting direction side.

[0098] The shapes and the materials of the spring member is notrestricted to this case, any type of modification can be acceptable.

[0099] [Third Preferred Embodiment]

[0100] The explanation about the third preferred embodiment of themagnetic tape cartridge according to the present invention will becarried out as below. In the following explanation, the components sameas explained in the first preferred embodiment is indicated by the samesymbols and the explanation thereof is omitted.

[0101] As shown in FIG. 8, a flection part 83 b (a supported part,pressed means) is formed at opening direction side of the spring arm 83of the spring member 8. This flection part 83 b is formed by bending thespring arm 83 upwardly at the tip part side and further bendingdownwardly at it's tip end.

[0102] As shown in FIG. 9, the upper half 3 is a case made of the sameresin as the lower half 2, and a side wall 31 having an opening 11, arib 33 for reinforcing, and the like are provided thereto. The position,the side wall 31 and the rib 33 are established, is determined so as tobe agreed with the side wall 21 and the rib 26 of the lower half withoutplay, when the upper half and the lower half are assembled together.

[0103] A guide groove (guide part) 32 a having the same width and thelength as the guide groove 22 a of the lower half 2 is provided betweenthe side wall 31 and the rib 33. The rib 33 is disposed along the sidewall 31. A projection part 34 (a spring supporting part) is disposed atthe end part in the opening direction side of the guide groove 32 a.

[0104] The projection part 34 is a plate having a nearly same thicknessas the width of the guide groove 32 a. A slope 34 b descending towardthe shutting direction side is provided at the end part in the shuttingdirection side of a top end 34 a. The top end 34 a is positioned at thelower half side (an upper side in FIG. 9) of the projection part 34. Asupporting face (a spring supporting face) 34 c prolonging toward thelower half 2 side is served at the end in the shutting direction side ofthe slope 34 b.

[0105] The attaching manner of the slide door 7 and the spring member 8to the cartridge case 1 will be carried out.

[0106] As shown in FIG. 10A, first, placing the slide door 7 and thespring member 8 to the guide groove 22 a of the lower half 2 in thecondition that the tip part of the spring arm 84 is fitting with thenotching part 72 of the slide door 7. At that time, the clearance isformed between the rib 26 and the flection part 83 b of the spring arm83 by shifing the slide door 7 to the side wall 25 side.

[0107] Next, as shown in FIG. 10B, sending down the upper half 3 to thelower half 2, the slide door 7 and the spring member 8 are arrangedthereon.

[0108] When the slope 34 b of the projection part 34 is set in touchwith the flection part 83 b of the spring member 8, the flection part 83b is moved toward the shutting direction side by the slope 34 b, andthus the spring member 8 is compressed.

[0109] When the upper half 3 is further sent downward, as shown in FIG.10C, the flection part 83 b of the spring member 8 is moved toward theshutting direction side as a result of the sliding movement along theslope 34 b of the prejection part 34. Then, the projection part 34 issent downward while sliding along the back side of the flection part 83b. Thus, the opening direction side of the spring member 8 is retainedby the supporting face 34 c.

[0110] Finally, engaging the upper half 3 with the lower half 2completely, the assembling operation of the upper half 3 and the lowerhalf 2 is thus achieved.

[0111] According to the present invention, the effectiveness as belowcan be obtained.

[0112] Since the flection part 83 b of the spring member 8 slid alongthe slope 34 b of the projection part 34 and is fit with the projectionpart 34 over the whole, the spring member 8 is compressed between theslide door 7 and the projection part 34. Therefore, the spring member 8is impelled to the shutting direction side.

[0113] The attaching operation of the spring member 8 and the slide door7 to the lower half 2 thus can be achieved without impelling the slidedoor 7 to the shutting direction side using a man work.

[0114] In the present embodiment, furthermore, the occurrence of thelifting movement of the slide door 7 caused by the urging force broughtby the spring member is prevented, and the attaching operation of theslide door 7 and the spring member 8 can be carried out with ease.

[0115] The present invention is not restricted to the above describedcase, and is represented by various embodiment.

[0116] (1) In the present embodiment, the projection part having theslope is served as the spring supporting part, and the spring memberhaving the flection part is served as the supported part and the pressedmeans. The present invention is not restricted to this case, forexample, the construction, only the spring supporting part is adopted,can be acceptable.

[0117] As an example of such case, as shown in FIG. 11, the projectionpart P1 can be adopted as the spring supporting part. This projectionpart P1 has a square pole shape and is prolonging downwardly from theend part in the opening direction side of the guide groove 32 a.

[0118] In this instance, the adoption of the sheet spring B2 formed inthe wave like shape and the slide door D2 having a rectangular plateshape, which are well-known in the conventional art, is preferable.

[0119] In the assembling manner of the magnetic tape cartridge havingsuch formation, first, placing the slide door D2 and the sheet spring B2on the guide groove 22 a. Next, sending down the projection part P1 fromabove at the opening direction side of the sheet spring B2, and pushingdown the slope part B21 by the edge of the projection part P1. Thus, thelower end of the slope part B21 is moved to the shutting direction sideand the sheet spring B2 is compressed.

[0120] As a result of the compression of the sheet spring B2, the slidedoor D2 is impelled to the shutting direction side.

[0121] In the present invention, furthermore, the combination as shownin FIG. 12 can be acceptable. In this combination, a helical torsioncoil spring B3, a slide door D2, and a spring supporting part areadopted. The helical torsion coil spring B3 has a zigzagged shape andthree of coil part B31 is provided at the flection part thereof. Theslide door D2 has a rectangular plate shape and a hooking hole D21, towhich an end part in the shutting direction side of the helical torsioncoil spring B3 is engaged, is bored thereto.

[0122] In this construction, the spring supporting part is composed of aprojection part P2, a hooking part P21, and a guide surface P22. Theprojection part P2 is provided at the opening direction side of theguide groove 32 a so as to be protruded downwardly. The hooking part P21of slit like shape is provided at the lower part of the projection partP2. The guide surface P22 is formed on the hooking part P21 for guidingthe end part in the opening direction side of the helical torsion coilspring B2.

[0123] In the assembling manner of the magnetic tape cartridge havingsuch construction, first, placing the helical torsion coil spring B3 andthe slide door D2, which are previously assembled together, on the guidegroove 22 a.

[0124] When the upper half 3 is pressed downward as hooking the end partof the helical torsion coil spring B3 on the hooking part P21 of theprojection part P2, the end part in the opening direction side of thehelical torsion coil spring B3 is moved downward.

[0125] As a result of this movement, the helical torsion coil spring B3is compressed, and thus the slide door D2 is impelled to the shuttingdirection side.

[0126] The combination as shown in FIG. 13 can be acceptable. In thiscombination, a slide door D2, a supporting shaft B4, a spring member B4,and a spring supporting part 34 are adopted. The slide door D2 has arectangular plate shape. A supporting shaft J is protruded from theslide door D2 towards the opening direction side. The spring member B4is wound around the supporting shaft J. The spring support part 34 iscomposed of the adjoined rectangular plate, which is same as abovedescribed projection part 34. In this construction, the spring supportpart 34 is provided so that the supporting shaft J is sandwiched betweenthere, and so that the end part in the opening direction of the springmember B4 is made contact with the spring support part 34.

[0127] In the assembling manner of the magnetic tape cartridge havingsuch construction, first, placing the slide door D2 on the guide groove22 a. On this occasion, the spring member B4 is previously fit on thesupporting shaft J of the slide door D2. Next, pushing the upper half 3downwardly in the condition that the supporting shaft J is sandwichedbetween two of projection part 34 and 34. Thus, since the end part inthe opening direction side of the spring member B4 is slid along theslope 34 b and 34 b, the spring member B4 is compressed toward theshutting direction side. As a result of the compression of the springmember B4, the slide door D2 is impelled to the shutting direction side.

[0128] (2) In the present embodiment, the projection part prolongingdownwardly from the guide groove of the upper half is served as thespring supporting part. The spring supporting part is not restricted tothis case, any type of modification can be adaptable as long as thecertain supporting of the spring member is achieved.

[0129] In the present invention, the construction as shown in FIG. 14 isadaptable. In this construction, a spring member B5, a slide door D2,and a spring supporting part are adopted. The spring member B5 has azigzagged shape and two of coil parts B51 are arranged at the flectionpart thereof. The slide door D2 has a rectangular plate shape and ahooking hole D21 for hooking the end part in the shutting direction sideof the spring member B5 is provided thereto. The spring supporting partis composed of a slit part 33 a and a slope 33 b. The slit part 33 a isdisposed on the rib 33 arranged along the guide groove 32 a of the upperhalf 3. The slope 33 b inclining toward the opening direction side isprovided at the opening direction side of the slit part 33 a.

[0130] In the assembling manner of the magnetic tape cartridge havingthis construction, first, placing the spring member B5 and the slidedoor D2, which are previously assembled together, on the guide groove 22a. Next, pressing the upper half 3 downwardly in the condition that theend part in the opening direction side of the spring member B5 is madecontact with the slope 33 b of the rib 33. Thus, the end part of thespring member B5 is slid toward the shutting direction side, and engagedwith the slit 33 a. Since the end part of the spring member B5 is slidand engaged with the slit 33 a, the spring member B5 is compressed.Thus, the slide door D2 is impelled to the shutting direction side.

[0131] (3) In the present embodiment, the flection part, which is formedat the tip of the spring arm of the spring member, is served as thepressed means. Another kind of means may be acceptable as long as it canmove the spring member to the shutting direction side by engaging withthe spring supporting part. For example, the manner, in which the caphaving a lock-and-key shape with respect to the guide part and made ofresin etc is arranged at the tip part of the spring arm, can beacceptable.

[0132] As shown in FIG. 15, furthermore, a slider S, which is disposedat the shutting direction side of the guide groove 22 a and which canslide along the guide groove 22 a, can be adopted as the pressed means.This slider S has a slope S1 which is parallel to the slope 34 b formedon the projection part of the upper half 3.

[0133] In this construction, when the upper half 3 is pressed downward,since the slider S is slid along the slope 34 b of the projection part34, the slider S is moved to the shutting direction side. As a result ofthe sliding movement of the slider S, the spring member B6 iscompressed, and thus the slide door 7 is impelled to the shuttingdirection side by the spring member B6. In the view of the manufacturingcost, however, it is preferable that the spring member and the pressedmeans are formed into the integral body.

[0134] (4) In the present embodiment, the flection part is formed bybending the end part side of the spring arm upward, and bending the tippart into the circular shape further. The shape of the flection part isnot restricted to this, for example, the shape, in which the tip part ofthe spring arm is bent so as to be parallel to the slope of theprojection part, can be acceptable.

[0135] (5) In the present embodiment, the spring member having two ofadjoining coil part, from which a spring arm is prolonged, respectively,is served as the spring member. The shapes and materials of the springmember is not restricted, and can be modified depending on the situationas long as the pressed means is at least disposed at either supportedpart.

[0136] (6) In the present embodiment, the projection part is disposed atthe end part in the opening direction side of the guide groove formed onthe upper half. The location of the projection part is not restricted tothis case as long as the slope of the projection part can be contactedwith the pressed means of the spring member.

[0137] Also, the modification of the shape of the projection part can becarried out arbitrarily. For example, the curved surface is acceptableas the shape of the slope of the projection part. In the presentembodiment, furthermore, the projection part is integrally formed withthe upper half, but not restricted to this case. It is acceptable thatthe projection part is provided at the upper half as the another member.

[0138] (7) In the present embodiment, the end part in the shuttingdirection side of the spring member is supported by the springsupporting means, but the present invention is not restricted to this,as long as either supported part of the spring member is supported.

[0139] For example, the construction shown in FIG. 16 can be acceptable.In this construction, a sheet spring B7 having a wave like shape, and aprojection part P3 having a recessed part P31 are adopted.

[0140] In this construction, the recessed part P31 of the projectionpart P3 is served as the spring supporting part. In this construction,furthermore, the sheet spring B7 is disposed between the rib 26 of thelower half 2 and the slide door D3 which slide on the guide groove 22 aof the lower half 2.

[0141] The slide door D3 has a length twice times longer than theoverall length of the sheet spring B7 and has a protruding part D31projecting toward the rib 26 side at the opening direction side thereof.Thus, the sheet spring B7 is attached to the slide door D3 by hookingthe end part in the opening direction side of the slide door D3 to theprotruding part D31.

[0142] In the assembling manner of the magnetic tape cartridge havingsuch construction, first, placing the sheet spring B7 and the slide doorD3, which are previously assembled together, on the guide groove 22 a ofthe lower half 2.

[0143] Next, pressing the upper half 3 downwardly while keeping theengagement between the protruding part B71 of the sheet spring B7 andthe recessed part P31 of the projection part P3. Thus, the protrudingpart 71 of the sheet spring B7 is moved in the shutting direction side,because the protruding part71 is pressed by the recessed portion P31.

[0144] As a result of the movement of the protruding part B71 of thesheet spring B7, since the sheet spring B7 is expanded, the slide doorD3 is impelled to the shutting direction side.

[0145] According to the present invention, since one end part of thespring member is guided to the spring engaging part by the guide partprovide at the one end part of the spring member, the sticking of theend part of the spring member with the slide door can be prevented. Thusthe automation of the product line of the magnetic tape cartridge can beachieved with ease.

1-2. (canceled).
 3. A magnetic tape cartridge comprising; an openingprovided on one side wall of a cartridge case, and is used for tapedrawing; a slide door slidably supported by a guide part disposed alongsaid one side wall, and said slide door is used for achieving theshutting-and-opening operation of said opening; and a spring member forimpelling said slide door to the shutting direction side, and is placedon said guide part; end part in the opening direction side of saidspring member is supported at the higher position than the shuttingdirection side.
 4. A magnetic tape cartridge according to claim 3,wherein said spring member impels said slide door trough a hooking holeprovided at the opening direction side of said slide door.
 5. A magnetictape cartridge according to claim 3, said magnetic tape cartridgefurther comprising; a slider stop for stemming the shutting directionend of said slide door, and is provided at another side wall; said slidedoor is impelled by said spring member at the lower position in heightthan the top end of said slider stop.
 6. A magnetic tape cartridgeaccording to claim 5, wherein said spring member impels said slide doortrough a hooking hole provided at the opening direction side of saidslide door. 7-10. (canceled).